condition mean min max ZT0-3 10.586879 10.586879 10.586879 ZT4-7 10.4870615 10.4870615 10.4870615 ZT8-11 10.347301999999999 10.347301999999999 10.347301999999999 ZT12-15 9.9860845 9.9860845 9.9860845 ZT16-19 8.2425225 8.2425225 8.2425225 ZT20-23 8.215878 8.215878 8.215878